Box stacker



June 13, 1939. J. w. STEVENSON 2,161,836

BOX STACKER 3 Sheets-Sheet 1 Filed Jan. 11, 1937 June 13, 1939. J. w.sTEv ENs oN BOX STACKER Filed Jan. 11, 1937 3 Sheets-Sheet 2 J. w.STEVENSON June 13, 1939.

BOX STACKER 3 Sheets-Sheet 5 Filed Jan. 11, 1937 Patented June 13, 19391 uurrso- STATES PATENT OFFICE ment of this designed for use in citruspacking houses is disclosed herein.

Citrus fruits are harvester by being picked-from the trees by hand andare brought to the packing house from the groves in what are known asfield boxes. At the packing house these loaded boxes are taken from thetruck and stacked on the floor in stacks of anywhere from five to eightboxes high. When it is desired to remove the fruit from these boxes andrun it through the series of treatments by which it is prepared formarket, the fruit of course must be dumped from the boxes containing itand the empty boxes delivered to empty box storage. Clamp trucks areprovided by which an entire stack of boxes can be very easily handledand moved from place to place on the packing house floor by a singleworker.

It is an object of my invention to provide a machine to which loadedboxes may be delivered in the form of stacks and which will dump thecontents from the boxes in these stacks and form the empty boxes intostacks for storage. 1

In stack dumpers previously in use, there has always been a pausebetween the dumping of the last box in a given stack and the first boxin the next stack which is longer than the interval between the dumpingof successive boxes in each stack. This resulted in irregular feeding offruit to the various machines for treating this, with correspondingdecrease in emciency in these machines.

It is therefore another object of my invention to provide a stackhandling device which will deliver individual boxes of a series ofstacks successively to a box dumper or other mechanism so that theinterval between the delivery of the last box of each stack and thefirst box in the next succeeding stack is the same as the intervalsbetween the delivery of successive boxes in a given stack.

The stacking of boxes in the citrus industry is not only necessary afterthe contents have been dumped from the box, but also when the boxes arefirst received from the groves into the packing house. It is, therefore,another object of my invention to provide a novel and efficient boxstacker which may be used either for handling loaded or empty boxes.

The manner of accomplishing the foregoing objects, as well as furtherobjects and advantages, will be made manifest in the followingdescription taken in connection with the accompanying drawings, inwhich:

Fig. 1 is a diagrammatic cross sectonal view of a preferred embodimentof my invention.

Fig. 2 is a. cross sectional view taken on the line 2-2 of Fig. 1.

Fig. 3 is a plan view of the upper portion of Fig. 1 showing the drivemechanism.

Fig. 4 is a side elevational view of Fig. 3 taken in the direction ofthe arrow 4 and illustrating that portion of the drive mechanism on thatside of the machine.

Fig. 5 is a diagrammatic fragmentary detail view of a rest disposed aswhen supporting a box in-dumping position.

Fig. 6 is a cross sectional view taken on the line 63 of Fig. 3.

Fig. '7 is an enlarged fragmentary cross sectional view illustratingadditional steps to those shown in Fig. 1 of the dumping of a box andjust after a new stack has been received into the machine.

Fig. 8'is an enlarged fragmentary cross sectional view of a portion ofthe apparatus shown in Fig. 1 and illustrating the ejection of a stackjust formed and the starting of a new stack;

Fig. 9 is a fragmentary perspective view illustrating a stack formingcradle of the stacker of my invention and the manner in which this oper-The stack feed conveyer 12 The stack feed conveyer I2 is mounted in afloor 20 upon which the frame ll rests and comprises a pair of chains 2|which pass around idle sprockets 22 and drive sprockets 23, the latterbeing fixed on stub shafts 24 with driven sprockets 25. Provided on thechains 2| are stack spacing lugs 26.

The stack elevator 13 The stack elevator l3 includes an endless chainmechanism 30 having a drive shaft 3|, stub shafts 32, and sprockets 33and 34 fixed on these shafts about which sprockets are trained endlesschains 35. Fixed on the shafts 32 and disposed outwardly from thesprockets 34 are drive sprockets (not shown) which are connected byendless chains 33 with the driven sprockets 25 so that whenever thesprockets 34 are rotated by the chains 35, the sprockets 25 are alsorotated thus setting in motion the box stack feed conveyer I2.

The chain mechanism 30 is mounted so as to be inclined away from thestack conveyor I2.

The space Just in advance of endless chain mechanism 30 may be termed astack elevating path 39. Bordering this path and located between theendless chains 36 Just back of the path 39 is an inclined back plate 31which is supported on the frame II by members 99. Also mounted on theframe I I and extending substantially parallel with the foremost flightsof the chains 35 are guides 4|. Back of the chains 35 are providedguides which are secured upon the frame II.

The stack elevator I3 also includes two stack lifting cradles 41 each ofwhich comprises a pair of right triangular frames 49 which are connectedat their right angular vertices by a cross bar 49. The lower, verticesof the triangular frames 49 are connected by a cross bar the extendingends of which are pivotally connected to thechains 35 so that each ofthe cradles 41 is supported on these chains. Extending ends of the bar49 form guide pins 5| which slide against inner faces of guides H asshown in Fig. 2.

When the chains 35 are caused to traverse their endless pathway by therotation of shaft 3|, each of the cradles 41 is caused to travelupwardly when it is disposed in the path 39, the cross bars 49 and 50being guided at this time between the. back plate 31' and the inner edgeportions of the guides 4|. During this upward travel of a particularcradle 41,, the center of gravity of that cradle, as well as any weightwhich might be imposed on it, maintains the pins 5| of such cradlepressed against the inner edge portions of the guides 4 I. Thus, as thiscradle is propelled upwardly above the sprocket 3|, it remains in thesame rising position in which the rising cradle is shown in Fig. 1 untilthe pins II thereof engage traps which start rocking this cradlerearwardly. The frames 49 of this cradle then engage the shaft 3Icausing the cradle to flop backward until the pins 5| engage guides 45as shown in Fig. 7.

Approaching the lower end of the chains 35, the downwardly moving cradle41 is swung forwardly by engagement of'the cradle frames 49 with a fixedbar 49. The center of gravity of the descending cradle 41 thus shiftsforward of the cross bar 50 of this cradle with the result that thecradle swings over until the pins 5| thereof I engage the lower ends ofthe guides H. A comare dumping bars 92 and 93.

plete cycle of travel of one of the cradles 41 has now been described.

The dumping mechanism 14 The dumping mechainsm I4 includes a fruitreceiving hopper 96 above which is supported a 'pair of rollers 66 and aroller 91 having arms 99 which are normally inclined downwardly. Theroller 61 has a short arm 69 extending in the opposite direction fromthe arms 69, the arm 69 having a pin 10 which is trapped in an elongatedeye II of a link 12, the lower end of which is pivoted on a short arm 13fixed on a free end of the shaft H (see Figs. 1 and 5). Journaled on theframe II (see Figs. 1, 3 and 4) is a shaft 19 having a drive sprocket I1and driven sprockets 19, the latter being connected by short endlesschains I9 to small sprockets 90 mounted on stub shafts 9|. Carriedbetween the two chains 19 A fulcrum bar 95 is fixed on the frame Justoutwardly from and on the same level as theroller 61.

The empty boa: convever 15 The empty box conveyer I 6 includes shafts 99and 91 which are Journaled on the frame II and provided with sprockets99 and 99. Mounted on suitable stub shafts so as to be in alignment withthe sprockets 99 and 99 are small sprockets 90 and 9I, endless chains 92encircling the sprockets thus in alignment. Carried by the chains 92 area plurality of empty box conveying bars-93. Provided on the frame II areguide rails 99 for supporting the lower flights of the chains 92 and boxrails 91 for supporting a box while it is being conveyed by one of thebars 93. For driving purposes the shafts 99 and 9'! are connected bysprockets 99 and 99 rigidly fixed on these shafts and an endless chainI00 encircling these sprockets. It might also be pointed, out here thatthe sprockets 99 are loosely mounted on the shaft 96 and the sprockets99 are fixed upon the shaft 91.

Fixed on the rear end of shaft 96 is a spur gear I06 and a sprocket I06,the latter being connected with the sprocket II by a chain I0l.'Journaled in suitable bearings provided on the frame II is a shaft I09having a spur gear I09 at one end which meshes with the spur gear I05and at the opposite end a sprocket I I0 and a drive pulley I II. Thesprocket II 0 is connected by an endless chain II2 to a sprocket II3mounted on the front endof the shaft 3I. The entire machine I0 isadapted to be driven by any suitable prime mover (not 'shown) byrotating the pulley III as by a belt II4.

Also fixed on the shaft 91 is a sprocket II9 which is connected by anendless chain II9 to a sprocket I20, the latter being fixed upon anothershaft I2I also journaled on the frame II. The shaft I2I has fixedthereon sprockets I22 which are connected by endless chains I23 tosprockets I24 provided on stub shafts I25 mounted on the frame II.Attached to and carried between the chains I23 is a box-leveler crossbar I26. Pivotally mounted at I2I on the frame II is a stack latch I29having a serrated foot I29 at its lower end.

The stacker 16 and empty stack cohveyer 17 United with the sprockets I33on the stub shafts I3I are other sprockets (not shown) which areconnected by endless chains I31 provided on a shaft I39 of the emptystack conveyer II. Shaft I39 has sprockets I39 which are connected byendless chains I 40 to sprockets III, the latter being mounted on ashaft I42, and thence about other sprockets to carry the chains I40about an endless path.

Secured on the end of the shaft 91 is a drive pinion I44 and inalignment with this is a sprocket I45 which is idly carried on a stubshaft I49 mounted on a bracket I4'I directly over the shaft 91. Thesprockets I44 and I45 are connected by an endless chain I 49 to asprocket I49 Provided on the frame II at the right-hand or I39 to drivesprockets fixed upon the front end of the shaft I30 (see front of thebox stacker I9 are cradle guides I55.

At the top of the stacker I6 is a pair of guides I5I and I59, the latterextending downwardly to the bottom of the stacker. The upper ends of theguides I59 which, as shown in Figs. 1 and 8, are secured to the upper,ends of the guides I 55.

have upwardly bent portions I59 -Pivotally'mounted on a shaft I80 is astack ejector I5I which comprises a pair of vertical members I82, 9.cross member I83 connecting the upper ends of these, and a pair ofelephant ears I54 as shown inFig. 8. Provided on'the shaft I50 is aweight I55 which tends at all times to return the ejector I5 I to itsreclining position in which its upper end rests in a recess provided inaframe member I85, as shown in Figs. 1 and 8.

Also provided on shaft I80 are leaf springs I51.

(see Fig. 1). I

Carried between the chains I34 isa pair of stack forming cradles I10,each of these cradles comprising a pair of triangular frames I1Iconnected by a bar I12 at the lower vertices of the triangular framesIN. This bar has laterally extending ends I13 which pivottally connectwith the chains I34 as shown in Fig. 8'. Also provided on the triangularframes "I are pins I14 and I15. The manner in which the cradles I10operate when the chains I34 travel about their endless path due torotation of the sprockets I32 and I33 is as follows. When either of thecradles I10 is travelling downwardly with the forward flights of thechains I34, the guide pins I14 engage the guides I55 until the framesI1I thereof engage the shaft I50 which swings this cradle rearwardly.The leaf springs I51 are in alignment with the pins I14 and are nowengaged by the latter to rock the cradle over with pins I14 inengagement with the guides I58. When either of the cradles approachesthe uppermost end of the chains I34 the guide pins I14 of this cra lepass into the forwardly bent portions of the guides I51 and I58 and thusswing this cradle forwardly bringing the pins I15 thereof against theelephant ears I54 of the box stack ejector I5I as shown in broken linesin Fig. 8 and in full lines in Fig. 9. This shifts the box stack ejectoroutwardly into vertical position and causes the pins I14 to run out frombetween the forward ends of the guides I51 and I58 and travel upwardlyalong the inner faces of the guides I55. As the' bar I12 of this cradlepasses upwardly over the sprockets I32 so as to lift this cradle intoits uppermost position, the pins I15 pass upwardly beyond the upperextremity of the elephant ears I54 thereby permitting the weight I55 toswing the stack ejector I5I back into its reclining position as shown infull lines in Figs. 1 and 8.

Operation To set in operation the combined box stack dumper and emptybox resta'cker I0, power is applied through the belt II4 to the pulleyIII so as to rotate the latter in the direction indicated by the arrowsin Figs. 3 and 4. This rotates the shaft I08 which through the sprocketsH0 and H3 and the chain II2 rotates the shaft 3I which sets in motionboth the stack elevator I3 and the stack feeder I2. Also, through thegears I08 and I05, the sprockets I05 and 11, and the chain I01, the boxdumping mechanism I4 is set in operation. As already noted, the rotationof the shaft 85 by the gears I05 and I08 transmits power through I44 onthe end of shaft 81 (see Fig. 4) drives the box stacker I5 through thechain I48 and the sprocket I48. As above mentioned, empty box stackconveyer I1 is connected to the stacker I5- so that when the stacker isoperated this also sets I in motion the empty stack conveyer I1.

When the machine I0 has thus been started, the attendant trucks stacksof boxes S from their place of storage on the floor of the packing houseand sets these down on the chains 2| of the feed conveyer I2 between thelugs 28 as shown in Fig. 1. The lugs 25 are so placed on the chains 2|that these stacks S are successively delivered, with the lowermost boxin the stack extending into the elevating path 35, just as one of thecradles 41 rises upwardly into position to support this stack, tilts itinto position in the path 35 against the back plate 31," and startselevating it upwardly towards the box dumping mechanism I4. The lattermechanism is so timed that as each of the boxes B in a stack S beingthus elevated comes into a certain position relative to the dumpingmechanism, which may be termed a dumping position, the bar 82 engagesthe side of this box and starts to tip it toward the right against angleiron fulcrum bar 85. As the bar 82 completes its tilting action on theside of thisbox, the bar 83 comes into play against the bottom of thebox and continues the rocking of the latter with the result that the boxis dumped over completely on its side, coming to rest temporarily in theposition shown in'broken lines I80 in Fig. 1.

After the box under discussion has remained in the position I80 asufficient length of time for the fruit to gravitate entirely therefrominto the hopper 55, the arms 58 are lifted by the downward movement ofthe short arm 13 and the engagement of the upper end of the eye H withthe pin 10 as shown in Fig. '1 in full lines. This lifts the box just asone of the cross bars 93 moves into contact with the empty box so thatthe later is immediately shifted, as indicated by the broken lines I85in Fig. '7, onto the rollers 55 and empty box rails 91,

As the first of the boxes is thus dumped and the empty box carried awayby one of the bars 83, the next box of the stack is being liftedupwardlyinto dumping position which is indicated by the broken lines I85 in Fig.'7. As the box reaches this position the cross bar 82 moves into contactwith the adjacent side of the box so as to initiate the dumping of thisbox as already described for the first box. In this manner the boxes ofthe stack S are successively elevated and dumped and the empty boxespropelled by convey- .ing bars 93 of the conveyer I5 along the empty ofthe lowermost box of the preceding stack as elapses between the dumpingof successive boxes in a given stack. Thus the dumping of fruit in theoperation of my machine I0 is at a. uniform rate, there being nofluctuation in the interval between the dumping of successive boxes solong the feed conveyer stacks S.

As shown in Fig. 1, each of the empty boxes is propelled by one of thebars 93 into a position where this box is just beyond the right hand endI2 is kept supplied with ofthe empty -box---rails I1 and disposeddirectly over the box stacker I, after which this bar ll passes aroundthe sprockets II and then upwardly parallel with the bottom of the box.From the time that this box first starts to project over the right-handends of the rails ll the'top of the box is engaged by the box levelerbar I" to support this box and prevent its falling to the right as therails 01 are no longer under the center of ravity of the box. when thisbox is entirely free from the rails '1, however, it is then free to movedownwardly and rock slightly into alignment with the box stacker ll.

Where this is the first box of a stack, one of cradles I" will be foundin its uppermost position as shown in full lines in Fig. 8 and this boxwill be'deposited directly upon this cradle. As

' will be recalled, each cradle I10 when in its uppermost position hasjust swung the stack ejector i ii into vertical stack ejecting positionas shown in Fig. 9, and then has released this to permit it to return tobroken line position it! as shown in Figs. 1 and 8. When this cradle,therefore, starts to move downwardly with the descending flights of thechains I, this first box of the stack is carried downwardly on thiscradle outside of the stack ejector IN as clearly shown in Fig. 1.

As successive boxes of a stack are dumped and the empties carried towardthe right, as shown in Fig. 1, these are successively positioned as thesecond box is shown in Fig. 1 overthe descending, partly formed stack ofempty boxes and dropped on the preceding box and thus added to the stackso that eventually the entire stack of loaded boxes have been emptiedand restacked in the formation of a stack of empty boxes. -This occursjust as the other of thecradles I" has returned upwardly to brlngitspins I'll between the guides I51 and I 58 thereby causing pins I15 ofthis cradle to engage the elephant ears I which shift the stack ejector"I into vertical position and eject this newly formed stack onto thechains 0 of the empty stack discharge conveyer II.

When thus ejected the stack is held against 45 rocking backward byengagement of the serrated foot II! of the stack latch I28 with theupper box as shown in Figs. 1 and 8. v

A complete cycle of operation of the machine Ill of my invention has nowbeen described. This 50 cycle is repeated automatically as long as thefeed conveyer I2 is supplied with stacks S of loaded boxes. Whilethestacker Ii of my invention is here shown as being used to stack emptyboxes,

and while these are shown as being stacked on 55 their sides, I do notdesire my invention to be restricted to this use of the stacker l6 asthis stacker maybe used to stack loaded boxes in upright position if itis so desired.

While I have shown but a singl embodiment of no my invention it isunderstood tha many changes and modiiicationsmight be made in this andthe -invention embodied in many diflerent forms withformed in said path,said ejecting means vertical away from'the direction towards which" saidstacks are to be delivered; endless'chain means disposed substantiallyparallel with and adjacent said path; a plurality oi stack supportingcradles pivotally mounted on said chain means; means for operating saidchain means and guiding said cradles to cause each of said cradiesinturn to be relatively quickly extended into said path adjacent itsupper end, lowered through said path until adjacent the lower end ofsaid path, swung out of said path, and elevated to a position adjacentthe upper end of saidpath; means for delivering boxes at regular timedintervals into a position at the upper end of said path from whichposition said boxes are permitted to move downwardly to form a stack ofboxes on each of said cradles as it travels downwardly through saidpath; and means for ejecting from said path each stack of boxes soformed in time to permit the one of saidcradles disposed upwardly insaid path to receive the next box from.

said position as the lowermost box in the next succeeding stack to beformed.

2. A combination as in claim 1 in which said stack ejecting means swingssaid stacks into vertical position in ejecting them from said path.

3. A combination as in claim 1 in which said stack ejecting means swingssaid stacks into vertical position in ejecting them from said path; andmeans forreceiving said stacks from said ejecting means and conveyingsaid stacks in close order away from said stack forming path.

4. A combination as in claim 1 in which said stack ejecting, means ispivotally mounted adjacent the lower end of said path and extendsrearwardly of said path while the stack is being being automaticallyswung into vertical position in delivering each stack from said path.

5. A combination as in claim 1 in which said stack ejecting means ispivotally mounted adjacent the lower end ofsaid path and extendsrearwardly of said path while the stack is being formed in said path,said ejecting means being automatically swung into vertical positionindelivering each stack from said path; and means for automaticallyreturning said ejecting means to its normal position behind said pathimmediately following the discharge of a stack of boxes so. as toprevent said ejecting means interfering with the formation of the nextstack of boxes.

6. A combination as in claim 1 in which said ejecting means is actuatedto eject a stack from said path in repsonse to the movement of one ofsaid cradles into said path.

JAMES'W. STEVENSON.

